This research is concerned with understanding the physiology of taste and cutaneous senses including the coding of the sensory information transmitted to the brain. One objective is to advance our understanding of the sense of taste in mammals, with particular reference to the hedonic properties of taste solutions. For example, what is the neural code which causes sweet taste solution to be preferred and bitter avoided? A second objective and the dominant focus of concern, is to elucidate the basis of the plasticity in the taste system evident both in regeneration and in the normal adult mammal. The interactions between taste nerve fibers and epithelial cells, which are precursors of taste receptor cells, include the differentiation and maintenance of the receptor cells (trophic dependence upon nerve supply) and events leading to the formation of appropriate synaptic connections with the receptor cells. A physiological model which can be used to assess the trophic maintenance of taste buds in brief periods is being exploited. Anatomical, physiological, biochemical and behavioral techniques will be brought to bear upon these problems.